Aeroplanes having wings capable of adjustment in sweep



Sept. 14, 1965 C. F. TOMS AEROPLANES HAVING WI NGS CAPABLE OF ADJUSTMENT IN SWEEP Filed Oct. 16, 1963 6 Sheets-Sheet 1 fly. 2.

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United States Patent 3,206,146 AEROPLANES HAVING WINGS CAPABLE OF ADJUSTMENT IN SWEEP Charles Frederick Toms, Luton, England, assignor to Hunting Aircraft Limited, Luton, England, a British company Filed Oct. 16, 1963, Ser. No. 316,654 Claims priority, application Great Britain, Oct. 16, 1962, 39,175/62 Claims. (Cl. 244-46) It has been found that aircraft with variable-sweep wings mounted upon fixed pivots, whether mounted inboard or outboard of the fuselage, suffer the disadvantages that unless the change in wing span dimension, and with outboard pivots the percentage of the wing area which undergoes sweep change, is to be disappointingly small, it is necessary to employ a geometry which, when the wings are moved between the fully outspread and fully swept positions, and vice versa, entails a marked change in the relative positions of the centres of pressure and gravity and a corresponding disturbance in the longitudinal stability characteristics of the aircraft; in addi tion, a loss in the eflective wing area may be experienced when the wings are moved to the outspread position.

The present invention is concerned with the provision of an alternative manner of wing/body mounting for variable-sweep wing aircraft by which the afore-mentioned disadvantages may be avoided, and for this purpose it is here proposed to provide means whereby, in executing an adjustment in sweep, the wings are each caused to rotate about a point X, fixed with respect to the wing, said point X having a translatory motion relative to the body by means effective to move said point X and a second point Y upon the wing root structure in relation to the body along separate substantially horizontal but relatively inclined lines preferably within the width of the body. One of said lines (hereinafter referred to as line A) is preferably parallel to the longitudinal plane of symmetry of the aircraft and determines the extent of the translatory motion of the wing root; the other line (hereinafter referred to as line B) is preferably straight and being inclined to line A, brings about a rotation of the wing about the point X which is moved along line A. Alternatively line B may be curved but such that a line joining its extremities is straight.

The two points X and Y are disposed so that the point Y is aft of the point X, the point X moving along line A and the point Y moving along line B. Line B is in such case disposed diagonally (as viewed in plan) so that when the wing is moved towards the fully swept position, the necessary translatory movement of the wing root being in a forward direction, the point Y is caused to move towards the longitudinal centre-line of the aircraft to bring about a reduction in span, the wing-tip turning inwardly about the point X. I

By these means a marked change in span is achieved when the wings are moved between the outspread and the fully swept positions, not only without loss in eifective wing area when the wings are outspread but even with an increase in nett wing area. The disturbance of the longitudinal stability characteristics of the aircraft is avoided and these can be optimised with the wing in any two sweep positions within the range provided.

The manner in which the invention may be carried into effect is hereinafter described in greater detail with reference to the accompanying diagrammatic drawings. In said drawings FIG. 1 is a plan of part of the body of an aeroplane having a single pair of wings mounted with capability of adjustment in sweep, the wings being shown in an outspread position, FIG. 2 is a similar view in which the wings are shown in an aft-swept position, and

Patented Sept. 14, 1965 FIGS. 3 and 4 are front views respectively corresponding to the two wing-sweep positions depicted in FIGS. 1 and 2. FIGS. 5 and 6 are respectively similar to FIGS. 1 and 2, but illustrate a modification hereinafter described.

FIG. 7 is a fragmentary plan view, drawn to a larger scale, illustrating the wing mountings and the mechanism ancillary thereto, and FIG. 8 is a section on the line VIIIVII[ of FIG. 7. FIG. 9 is a view, mainly in side elevation, of the parts shown in FIG. 7; FIG. 10 is a partly sectional perspective View of part of FIG. 7 but with the wings shown in the outspread position; and FIG. 11 is a detail of the sweep-locating members of one of the wings.

It will be seen by reference to FIGS. 1 to 6 that the aeroplane comprises a body 20, the nose 201 of which is shown only in FIGS. 1, 3, 4 and 5, and a single pair of port and starboard wings which are respectively designated by the numerals 21 and 22. Each wing 21 or 22 has points of pivotal attachment to the body 20 at X and Y. The pivots X of both wings are mounted upon a common saddle 23 which is free to move slidably in a direction parallel to the longitudinal axis of the body 20 in guides 24, which guides are indicated in FIGS. 1, 2, 5 and 6 by the chain-dotted lines A, A. The movement of said saddle 23 in said guides 24 is efiected by a screwjack 25 which is supported at its after end in a thrustbearing 251 and operated by a motor 26, and the saddle is supported between the surfaces of the guides by means of rollers 27, 28 and 281 (FIGS. 7, 8 and 9). A comparison of FIGS. 1 and 2, or FIGS. 5 and 6, will show the extent of the translatory movement of the pivots X, X in consequence of the rotatory movement of the wings 21, 22 between the outspread position of FIGS. 1 and 5, and the swept-aft position of FIGS. 2 and 6.

The pivotal attachments between the wings and the body at Y, Y are guided for movement along separate but relatively inclined lines B and B (FIGS. 1, 2, 5 and 6) within the width of the body. Such guided movement along the lines B, B is determined in respect of each wing by a track 29 provided on the body and arranged to co-operate with a sweep-locating member 30 fixed on the wing. Said tracks 29 are inclined to the guides 24, and are effective to bring about a rotation of the wings about the respective pivots X, X as these are translated along the lines A, A, by reason of the fact that as the pivots X, X move forwardly when the wings are swept aft, the pivots Y, Y are caused to approach the longitudinal centre-line and thereby result in the necessary reduction in span.

It is a remarkable feature of the invention that the considerable change of span which is achieved when the wings are moved from the outspread to the fully swept positions respectively shown in FIGS. 1 and 2 (or in FIGS. 5 and 6) may result in a decrease in nett wing area, and of course during the reverse movement of the wings from the fully swept to the outspread position there is a corresponding increase in the nett wing area. Drag loads are resisted by the engagement of the members 30 in the tracks 29.

The lines B, B of the tracks 29, 29 may be substantially horizontal, but in the preferred embodiment shown in FIG. 9 they are shown as being slightly inclined in a forward direction, an arrangement which may prove desirable in certain circumstances where it is required that alterations in sweep of the wings should be accompanied by automatic changes in dihedral and/or incidence, and such automatic changes may be obtained by adopting a suitable direction for the axes of the pivots X to the vertical, in which case it may be necessary to provide the sweep-locating members 30 with means whereby they may undergo a certain telescopic contraction or expansion during their movement along the tracks 29. For example, each such member 30 may include a stem 301 mounted telescopically in the holder 302 and terminating in a spherical slipper 303 which is received within a conformably shaped groove 291 of the track 29.

Reference to FIG. 11 shows that the stem 301 of the member 30 carries at its upper end a piston 304 which is arranged to slide in a cylinder 305 which is part of the holder 302. The chambers of said cylinder on opposite sides of said piston respectively communicate by passages 306, 307 with a supply-pipe 308 by which they may be connected to a pressure-fluid system, a stop valve being interposed at 309. Suitable means are provided for setting said valve in either a closed or an open position. In operation, when the wings occupy a desired sweep condition, the valve 309 is closed and the piston 304 is locked. Since telescopic movement of the member 30 is consequently prevented, this member is likewise locked. Before initiating a wing-sweep adjustment, the valve 309 is opened and hydraulic liquid now being free to flow between the aforesaid chambers of the cylinder 305, the piston 304 is enabled to move telescopically as the wing draws closer to or away from the track 29 by reason of the inclination of its pivot X. The degree of control established over the flow of the hydraulic liquid in the open position of the valve 309 is effective to damp undesirable movement of the wing due to flight loads during alterations in sweep angle. When the desired sweep angle has been reached, the valve 309 is re-closed to lock the member 30.

FIGS. 5 and 6 illustrate a modification in which subsidiary locating means are provided, a member Z upon each wing being arranged to move along a curved track C, as the wing is adjusted in sweep between the outspread and swept-aft positions.

What I claim as my invention and desire to secure by Letters Patent is:

1. An aeroplane having a body and wings extending from said body and mounted upon pivots with capability of adjustment in sweep, and comprising means whereby for the purpose of executing such an adjustment, the wings are each caused to rotate about a first pivot axis which is fixed with respect to the wing and having a translatory motion relative to the body, further means being provided for moving said first pivot axis and a second pivot axis upon the wing root structure in relation to the body along separate substantially horizontal but 4 relatively inclined straight lines within the width of the body.

2. An aeroplane as claimed in claim 1, wherein in relation to each wing one of said relatively inclined lines is parallel to the longitudinal plane of symmetry of the aircraft.

3. An aeroplane as claimed in claim 2, wherein the second pivot axis associated with each wing is closer to the tip of that wing than the first pivot axis of that wing, and wherein in the course of the translatory movement of the wing root in a forward direction, the second pivot axis moves towards the longitudinal centre-line so as to turn the wing-tip inwardly to effect a reduction in span.

4. An aeroplane as claimed in claim 3, wherein the first pivot axis of each wing is carried upon a member mounted for slidable movement within the body along the longitudinal centre-line thereof, and comprising power-actuated means directly connected to said member for effecting said sliding movement of said member, and in respect of each wing a track extending within the body in a diagonal direction with respect to said centre-line, and a slipper member arranged to co-operate with said track during the sliding movement of said member.

5. An aeroplane as claimed in claim 1 wherein the directions of said first pivot axis provide a given range of dihedral angle and incidence setting between the swept aft and fully outspread positions, and comprising hydraulic lock means for releasably locking said wings at said second pivot axis thereof when said wings are in a selected position and releasing said wings for hydraulically damped movement along said second pivot axis, respectively, during a change in the position of said Wings.

References Cited by the Examiner UNITED STATES PATENTS 2,695,144 11/54 Woods 24446 2,699,3 00 1/55 Trotter et al 244-46 2,794,608 6/57 Johnson 244-46 2,83 6,381 5/58 Carrillo 24443 FOREIGN PATENTS 699,043 10/ 5 3 Great Britain.

MILTON BUCHLER, Primary Examiner.

FERGUS S. MIDDLETON, Examiner. 

1. AWN AEROPLANE HAVING A BODY AND WINGS EXTENDING FROM SAID BODY AND MOUNTED UPON PIVOTS WITH CAPABILITY OF ADJUSTMENT IN SWEEP, AND COMPRISING MEANS WHEREBY FOR THE PURPOSE OF EXECUTING SUCH AN ADJUSTMENT, THE WINGS ARE EACH CAUSED TO ROTATE ABOUT A FIRST PIVOT AXIS WHICH IS FIXED WITH RESPECT TO THE WING AND HAVING A TRANSLATORY MOTION RELATIVE TO THE BODY, FURTHER MEANS BEING PROVIDED FOR MOVING SAID FIRST PIVOT AXIS AND A SECOND PIVOT AXIS UPON THE WING ROOT STRUCTURE IN RELATION TO THE BODY ALONG SEPARATE SUBSTANTIALLY HORIZONTAL BUT RELATIVELY INCLINED STRAIGHT LINES WITHIN THE WIDTH OF THE BODY. 